The field of art to which this invention pertains is the hydrocracking of a hydrocarbonaceous feedstock to produce lube basestock. Petroleum refiners often produce desirable products such as lube basestock by hydrocracking a hydrocarbon feedstock derived from crude oil, for example. Feedstocks most often subjected to hydrocracking are gas oils and heavy gas oils recovered from crude oil by distillation. A typical gas oil comprises a substantial portion of hydrocarbon components boiling above about 700xc2x0 F., usually about 50 percent by weight boiling above 700xc2x0 F. A typical vacuum gas oil normally has a boiling point range between about 600xc2x0 F. and about 1050xc2x0 F.
Hydrocracking is generally accomplished by contacting in a hydrocracking reaction vessel or zone the gas oil or other feedstock to be treated with a suitable hydrocracking catalyst under conditions of elevated temperature and pressure in the presence of hydrogen so as to yield a product containing lube basestock.
Although a wide variety of process flow schemes, operating conditions and catalysts have been used in commercial activities, there is always a demand for new methods including hydrocracking to produce lube basestock which provide lower costs and higher product yields and quality. The integrated process of the present invention improves the economics for the production of lube basestocks.
U.S. Pat. No. 5,980,729 (Kalnes et al) discloses a hydrocracking process which utilizes a hot, high-pressure stripper.
U.S. Pat. No. 4,194,964 (Chen et al) discloses a process for the simultaneous distillation and hydrocracking of hydrocarbon feeds in a single vessel.
The present invention is a process for the production of lube oil basestock wherein a high boiling hydrocarbonaceous feedstock is hydrocracked to produce hydrocarbons boiling in the range of lube oil basestock and the resulting hydrocracker effluent is hot, hydrogen stripped to remove lower boiling hydrocarbons and hydrogen sulfide before being introduced into a hydrodewaxing zone. In a preferred embodiment the hot hydrogen stripper contains a hydrogenation zone conducted at xe2x80x9csweetxe2x80x9d hydrogenating conditions which permits the subsequent use of sulfur sensitive catalysts in downstream reaction zones including hydrodewaxing and hydrofinishing reaction zones. Preferably, the effluent from the hydrodewaxing reaction zone is immediately further processed in a hydrofinishing reaction zone.
In accordance with one embodiment, the present invention relates to a method to produce lube oil basestock from a hydrocarbonaceous feedstock which method comprises: (a) contacting the hydrocarbonaceous feedstock and a hydrogen-rich gaseous stream in a hydrocracking zone with a hydrocracking catalyst at a temperature from about 400xc2x0 F. to about 900xc2x0 F., a pressure from about 500 psig to about 2500 psig, and a liquid hourly space velocity from about 0.1 hrxe2x88x921 to about 15 hrxe2x88x921; (b) passing the effluent stream from the hydrocracking zone directly to a hot, high-pressure stripper utilizing a hot, hydrogen-rich stripping gas to produce a first vapor stream comprising hydrogen, hydrogen sulfide, ammonia and hydrocarbonaceous compounds boiling at a temperature below the boiling range of the lube basestock, and a first liquid stream comprising hydrocarbonaceous compounds boiling in the range of the lube basestock and saturated with hydrogen; (c) passing at least a portion of the first liquid stream and a hydrogen-rich gaseous stream to a catalytic hydrodewaxing zone to reduce the pour point of the first liquid stream; and (d) separating the resulting effluent from the catalytic hydrodewaxing zone to produce lube basestock.
In accordance with another embodiment, the present invention relates to a method to produce lube oil basestock from a hydrocarbonaceous feedstock which method comprises: (a) contacting the hydrocarbonaceous feedstock and a hydrogen-rich gaseous stream in a hydrocracking zone with a hydrocracking catalyst at a temperature from about 400xc2x0 F. to about 900xc2x0 F., a pressure from about 500 psig to about 2500 psig, and a liquid hourly space velocity from about 0.1 hrxe2x88x921 to about 15 hrxe2x88x921; (b) passing the effluent stream from the hydrocracking zone directly to a hot, high-pressure stripper utilizing a hot, hydrogen-rich stripping gas to produce a first vapor stream comprising hydrogen, hydrogen sulfide, ammonia and hydrocarbonaceous compounds boiling at a temperature below the boiling range of the lube basestock, and a downwardly flowing liquid comprising hydrocarbonaceous compounds boiling in the range of the lube basestock; (c) simultaneously contacting the downwardly flowing liquid in the hot, high-pressure stripper with a hydrogenation catalyst and an upwardly flowing hydrogen stream to produce a first liquid stream comprising hydrocarbonaceous compounds boiling at a temperature in the range of the lube basestock and saturated with hydrogen; (d) passing at least a portion of the first liquid stream and a hydrogen-rich gaseous stream to a catalytic hydrodewaxing zone to reduce the pour point of the first liquid stream; and (e) separating the resulting effluent from the catalytic hydrodewaxing zone to produce lube basestock.
In yet another embodiment, the present invention relates to a method to produce lube oil basestock from a hydrocarbonaceous feedstock which method comprises: (a) contacting the hydrocarbonaceous feedstock and a hydrogen-rich gaseous stream in a hydrocracking zone with a hydrocracking catalyst at a temperature from about 400xc2x0 F. to about 900xc2x0 F., a pressure from about 500 psig to about 2500 psig, and a liquid hourly space velocity from about 0.1 hrxe2x88x921 to about 15 hrxe2x88x921; (b) passing the effluent stream from the hydrocracking zone directly to a hot, high-pressure stripper utilizing a hot, hydrogen-rich stripping gas to produce a first vapor stream comprising hydrogen, hydrogen sulfide, ammonia and hydrocarbonaceous compounds boiling at a temperature below the boiling range of the lube basestock, and a downwardly flowing liquid comprising hydrocarbonaceous compounds boiling in the range of the lube basestock; (c) simultaneously contacting the downwardly flowing liquid in the hot, high-pressure stripper with a hydrogenation catalyst and an upwardly flowing hydrogen stream to produce a first liquid stream comprising hydrocarbonaceous compounds boiling at a temperature in the range of the lube basestock and saturated with hydrogen; (d) passing at least a portion of the first liquid stream and a hydrogen-rich gaseous stream to a catalytic hydrodewaxing zone to reduce the pour point of the first liquid stream; (e) passing the effluent directly from the catalytic hydrodewaxing zone into a hydrofinishing reaction zone; and (f) separating the resulting effluent from the hydrofinishing reaction zone to produce lube basestock.
Other embodiments of the present invention encompass further details such as types and descriptions of feedstocks, hydrocracking catalysts, hydrodewaxing catalysts, hydrofinishing catalysts and preferred operating conditions including temperatures and pressures, all of which are hereinafter disclosed in the following discussion of each of these facets of the invention.